CN115856456B - Cable charge test data transmission method - Google Patents
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- CN115856456B CN115856456B CN202310167266.4A CN202310167266A CN115856456B CN 115856456 B CN115856456 B CN 115856456B CN 202310167266 A CN202310167266 A CN 202310167266A CN 115856456 B CN115856456 B CN 115856456B
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Abstract
The invention relates to a cable charge test data transmission method, which belongs to the technical field of data transmission, and comprises the following steps: acquiring a change curve of charge density of each section of cable in the cable to be tested along with the propagation time of the sound wave; calculating the degree of abnormality of each section of cable insulating layer by using the change curve; calculating the overall abnormality degree of each section of cable according to the abnormality degree of each section of cable insulating layer and the abnormality degree of each section of cable at each moment in the period from the transmission of sound waves to the inner surface of each section of cable insulating layer to the outer surface of each section of cable core insulating layer, and carrying out Huffman coding according to the overall abnormality degree of each section of cable; the Huffman coding sequence is adjusted according to the overall abnormality degree of each section of cable, so that the data coding sequence with larger abnormality degree is shorter, and the transmission safety of the data with larger abnormality degree is ensured.
Description
Technical Field
The invention belongs to the technical field of data transmission, and particularly relates to a cable charge test data transmission method.
Background
With the development of society, the electricity demand is continuously promoted, the power transmission cable has risen to extremely important position, and after the cable is put into operation, the cable can break down when the life time has not been reached because of the influence of many aspects factor, therefore it is extremely important to test and in time seek cable trouble recovery power supply to high voltage cable, and judge the ageing condition of cable insulation usually carries out analysis through measuring the decay degree of space charge in cable, the speed of data transmission to the technicians in the test simultaneously also can exert certain influence to the efficiency of fault analysis to a certain extent, and data is to compress through conventional Huffman coding before transmission and improves transmission speed.
For the test data of the cable charges, the fault position can be accurately found by carrying out sectional test on the fault cable, so that the generated data is extremely large, huffman coding is based on the sequence and probability of the data, in the process of storing and transmitting all the data, the coding sequence is overlong due to the fact that the occurrence frequency of important data is too low, partial data is easy to lose due to network fluctuation in the process of data transmission, and therefore technicians are influenced to timely analyze the data in the cable test.
Disclosure of Invention
The invention provides a cable charge test data transmission method which is used for solving the problem that important data are easy to lose when test data of cable charges are transmitted in the prior art.
The invention relates to a cable charge test data transmission method which adopts the following technical scheme:
acquiring a change curve of charge density of each section of cable in the cable to be tested along with the propagation time of the sound wave, and simultaneously acquiring a first moment when the sound wave propagates to the outer surface of each section of cable insulation layer, a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer and a third moment when the sound wave propagates to the outer surface of each section of cable core insulation layer;
recording a time period between a first time and a second time of each section of cable as a first time period;
recording the time period between the second time and the third time of each section of cable as a second time period;
taking the minimum value of the charge density of the change curve corresponding to each section of cable in the first period as the charge density of the center of the insulating layer of each section of cable;
calculating the degree of abnormality of each section of cable insulating layer according to the charge density of the center of each section of cable insulating layer and the standard charge density of the center of the preset cable insulating layer;
calculating the degree of abnormality of each section of cable at each moment in the second period according to the charge density of each section of cable at each moment in the second period of the change curve corresponding to each section of cable, a charge density decay function of a preset cable during production test and the charge density corresponding to the first moment;
calculating the overall abnormality degree of each section of cable according to the abnormality degree of each section of cable insulating layer and the abnormality degree of each section of cable at each moment in the second period;
and constructing a Huffman tree according to the overall anomaly degree of all the sections of cables in the cable to be tested from high to low, and carrying out Huffman coding and transmission according to the constructed Huffman tree.
Further, the step of acquiring a first time when the sound wave propagates to the outer surface of each section of cable insulation layer, a second time when the sound wave propagates to the inner surface of each section of cable insulation layer, and a third time when the sound wave propagates to the outer surface of each section of cable core insulation layer comprises:
the moment corresponding to the first wave crest in the change curve is used as the first moment when the sound wave propagates to the outer surface of each section of cable insulation layer;
calculating a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer according to the preset standard thickness of the cable insulation layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulation layer;
and calculating a third moment when the sound wave propagates to the outer surface of each section of cable core insulating layer according to the preset standard distance between the outer surface of the cable core insulating layer and the outer surface of the cable insulating layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulating layer.
Further, the step of calculating the degree of abnormality of each section of the cable insulation layer includes:
calculating a first difference value between the charge density of the center of each section of cable insulation layer and the standard charge density of the center of the preset cable insulation layer;
calculating a first ratio of a first difference value corresponding to each section of cable to a standard charge density of the center of a preset cable insulating layer;
and taking the absolute value of the first ratio corresponding to each section of cable as the degree of abnormality of the insulating layer of each section of cable.
Further, the calculation formula of the degree of abnormality of each section of cable at each time in the second period is:
wherein, the liquid crystal display device comprises a liquid crystal display device,
indicate->
The segment cable is +.>
Degree of temporal anomalies; />
Indicate->
The corresponding change curve of the segment cable is +.>
The charge density at time; />
Representing the charge density decay function of the preset cable at the production test as +.>
A value corresponding to the moment; />
Indicating the propagation of sound waves to the +.>
The charge density corresponding to the first time of the segment cable.
Further, the step of calculating the overall degree of anomaly for each segment of cable includes:
accumulating the abnormal degree of each section of cable at each moment in the second period to obtain the accumulated value of all the abnormal degrees of each section of cable at all moments in the second period;
and adding the accumulated value of all the time abnormal degrees of each section of cable in the second period to the abnormal degree of each section of cable insulating layer to obtain the integral abnormal degree of each section of cable.
Further, the step of constructing the huffman tree according to the order from high to low by the overall anomaly degree of all the sections of the cable in the cable to be tested comprises the following steps:
sequencing the overall abnormal degrees of all sections of cables in the cable to be tested according to the sequence from high to low to obtain an overall abnormal degree sequence;
taking a first overall anomaly degree value in the overall anomaly degree sequence as a first layer of the Huffman tree, taking a second overall anomaly degree value in the overall anomaly degree sequence as a tree node on the left side of the second layer of the Huffman tree, and taking a third overall anomaly degree value in the overall anomaly degree sequence as a tree node on the right side of the second layer of the Huffman tree, thus completing the construction of the Huffman tree in turn.
Further, the step of obtaining a change curve of the charge density of each section of the cable to be tested with the propagation time of the sound wave includes:
and transmitting sound waves by using the coaxial cable space charge measuring device, and testing the change curve of the charge density of each section of cable along with the propagation time of the sound waves.
The beneficial effects of the invention are as follows:
according to the cable charge test data transmission method provided by the invention, a change curve of charge density of each section of cable in a cable to be tested along with acoustic wave propagation time is firstly obtained, and then a first time period between the time when acoustic waves propagate to the outer surface of each section of cable insulation layer and the time when acoustic waves propagate to the inner surface of the cable insulation layer is obtained according to the change curve and priori knowledge; simultaneously acquiring a second time period between the time when the sound wave propagates to the inner surface of each section of cable insulation layer and the time when the sound wave propagates to the outer surface of the cable core insulation layer;
determining a first period of time when the sound wave penetrates through the cable insulation layer and a second period of time when the sound wave continuously penetrates through the cable inner space until the sound wave contacts the cable core after penetrating through the cable insulation layer, wherein the charge density of the center of the cable insulation layer is the minimum value of the first period of time according to priori knowledge, so that the minimum value of the charge density of each section of cable corresponding to the change curve in the first period of time is used as the charge density of the center of each section of cable insulation layer; because the charge density in the center of the cable insulating layer reflects the insulation degree of the cable at the moment, when the cable is damaged or aged, the charge density in the insulating layer corresponding to the cable insulating layer is increased, and the amplitude of the charge density in the center of the insulating layer reflects the abnormality degree of the cable insulating layer to a certain extent;
under normal conditions, when no direct current voltage is applied, space charge distribution exists between the cable insulating layers, but after the direct current voltage is applied, the internal charge density of the cable insulating layers has a relatively stable attenuation trend, namely the outer surface of the cable insulating layers is increased to the wire core to a certain extent, and then the attenuation trend is shown until the attenuation trend is zero, although the attenuation trend has smaller fluctuation, the overall characteristics of the data are approximately the same, but if the cable has the problems of aging, breakage and the like, the characteristic of the cable is that the attenuation speed is slow, or the characteristic of dense space charge distribution on one section is shown, so that the abnormal degree of each section of cable at each moment in a second period is calculated based on the characteristic; the abnormal degree of each section of cable at each moment in the second period is the abnormal degree of the acoustic wave transmitted to the inner space of the section of cable at each moment, so that the abnormal degree of each section of cable insulation layer and the abnormal degree of each section of cable at each moment in the second period are utilized to calculate the overall abnormal degree of each section of cable;
because the test data of the cable charge is a large amount, and the Huffman coding is based on probability coding, the coding sequence is overlong because the occurrence frequency of important data is too low, and the important data is easy to lose due to network fluctuation in the data transmission process; in order to avoid losing important data, after the integral abnormal degree of each section of cable is calculated, the coding sequence of the section of cable in the whole cable is adjusted according to the integral abnormal degree of each section of cable, so that the shorter the data coding sequence with higher abnormal degree is, the faster the corresponding transmission speed is, and the transmission safety of the data with higher abnormal degree is ensured.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram showing the overall steps of an embodiment of a cable charge test data transmission method according to the present invention;
FIG. 2 is a schematic diagram showing the distribution of space charges in a cable under different DC voltage conditions;
FIG. 3 is a schematic cross-sectional view of a cable to be tested according to the present invention;
fig. 4 is a schematic diagram of huffman tree construction according to the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
An embodiment of a cable charge test data transmission method of the present invention is shown in fig. 1, and the method includes:
s1, acquiring a change curve of charge density of each section of cable in the cable to be tested along with acoustic wave propagation time, and simultaneously acquiring a first moment when acoustic waves propagate to the outer surface of each section of cable insulation layer, a second moment when acoustic waves propagate to the inner surface of each section of cable insulation layer and a third moment when acoustic waves propagate to the outer surface of each section of cable core insulation layer.
The step of obtaining the change curve of the charge density of each section of cable in the cable to be tested along with the propagation time of the sound wave comprises the following steps: and transmitting sound waves by using the coaxial cable space charge measuring device, and testing the change curve of the charge density of each section of cable along with the propagation time of the sound waves.
The step of acquiring a first moment when the sound wave propagates to the outer surface of each section of cable insulation layer, a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer and a third moment when the sound wave propagates to the outer surface of each section of cable core insulation layer comprises the following steps: the moment corresponding to the first wave crest in the change curve is used as the first moment when the sound wave propagates to the outer surface of each section of cable insulation layer; calculating a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer according to the preset standard thickness of the cable insulation layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulation layer; and calculating a third moment when the sound wave propagates to the outer surface of each section of cable core insulating layer according to the preset standard distance between the outer surface of the cable core insulating layer and the outer surface of the cable insulating layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulating layer.
In the cable production process, in order to prevent space charges from being generated in the insulation, the cable is heated and degassed in vacuum for a long time to decompose and volatilize most of impurities in the insulation, so the measurement content is mainly distribution information of the space charges in the cable under different applied voltage conditions, as shown in fig. 2, and the distribution curve diagram of the space charges in the cable under different applied direct current voltage conditions is shown in the invention
And under the voltage condition, transmitting sound waves by using a coaxial cable space charge measuring device, and testing the change curve of the charge density of each section of cable along with the propagation time of the sound waves.
In the change curve of the charge density of each section of cable in the cable to be tested along with the propagation time of the sound wave, the abscissa of the change curve is the propagation time of the sound wave
The unit is->
The ordinate of the change curve is charge density +.>
The unit is->
It should be noted that, except for the changed dc voltageExcept for the size, the other parameters not mentioned are the same in size, such as temperature, pressurization time, etc. At the same time, since the normal production parameters of the cable can be known when the cable is tested, the parameter information of the cable, namely the structure layer structure of the cable and the thickness r of each layer, and the space charge attenuation function of the normal cable in the production test are required to be obtained in advance>
。
For the sake of understanding, the meaning of the abscissa is explained herein, and as shown in fig. 3, which is a schematic cross-sectional view of the cable to be tested according to the present invention, the internal space charge of the cable is measured by emitting sound waves, and the transmission direction of the sound waves is indicated by the arrow in the horizontal direction in the figure, that is, the sound waves are directed from the surface of the cable to the cable core, and the time of the abscissa can be regarded as the position where the sound waves are located because the transmission speed of the sound waves is uniform. According to prior knowledge, the sound wave position corresponding to the wave crest at the moment 0 in fig. 2 is the outer surface of the cable insulation layer, the central position of the cable insulation layer is the position of the wave trough next to the sound wave position, the inner space of the cable is next to the sound wave position, and the second position of the wave trough is more obvious and corresponds to the cable core insulation layer.
S2, recording the time period between the first time and the second time of each section of cable as a first time period.
After the change curve is obtained, the moment corresponding to the first wave crest in the change curve is taken as the moment when the sound wave propagates to the outer surface of each section of cable insulation layer, the moment corresponding to the first wave crest in the change curve is taken as 0 moment, and because the transmission speed of the sound wave measured by the coaxial cable space charge measuring device is uniform and the structural information in the same cable is the same, the moment when the sound wave reaches the cable inner surface insulation layer and the cable core surface insulation layer under the condition of not changing the environment temperature is a determined value, and therefore, the thickness of the insulation layer is determined according to an empirical value
The transmission speed of the applied sound wave is +.>
Calculating to obtain the propagation time of sound wave in the insulating layer of the inner surface of the cable as +.>
I.e. correspond to->
In the range of the charge distribution density of the insulating layer on the inner surface of the cable, while at the same time +.>
At the moment, the sound wave just reaches the second moment on the inner surface of the cable insulation layer; when->
The first period of time, i.e., the period of time between the time that the sound waves propagate to the outer surface of each segment of the cable insulation layer and the time that the sound waves propagate to the inner surface of the segment of the cable insulation layer.
And S3, recording the time period between the second time and the third time of each section of cable as a second time period.
Obtaining the distance between the insulating layer on the surface of the wire core and the surface of the cable
Calculating the time when the sound wave reaches the insulation layer on the surface of the wire core, namely +.>
In which the space charge distribution information of the cable interior is calculated, i.e.>
The method comprises the steps of carrying out a first treatment on the surface of the Wherein the method comprises the steps of
When the sound wave reaches the outer surface of the cable core insulating layer, the corresponding time range of the space charge in the cable is obtained
For a second period of time, i.e. the propagation of sound waves into the inner surface of each cable insulation layerThe time period between the face moment and the moment when the acoustic wave propagates to the outer surface of the insulation layer of the cable core.
And S4, taking the minimum value of the charge density of the change curve corresponding to each section of cable in the first period as the charge density of the center of the insulating layer of each section of cable.
From a priori knowledge, the charge density is the smallest when the acoustic wave propagates to the center of the cable insulation layer, and the first period is the period between the time when the acoustic wave propagates to the outer surface of each section of cable insulation layer and the time when the acoustic wave propagates to the inner surface of the cable insulation layer, so that
The smallest value in the range is +.>
I.e. +.>
Indicating the charge density at the time corresponding to the center of the insulating layer.
S5, calculating the abnormality degree of each section of cable insulation layer according to the charge density of the center of each section of cable insulation layer and the standard charge density of the center of the preset cable insulation layer.
The step of calculating the degree of abnormality of each section of cable insulation layer comprises: calculating a first difference value between the charge density of the center of each section of cable insulation layer and the standard charge density of the center of the preset cable insulation layer; calculating a first ratio of a first difference value corresponding to each section of cable to a standard charge density of the center of a preset cable insulating layer; and taking the absolute value of the first ratio corresponding to each section of cable as the degree of abnormality of the insulating layer of each section of cable.
The calculation formula of the degree of abnormality of each section of cable insulation layer is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
indicate->
Degree of abnormality of the segment cable insulation layer; />
Indicate->
Charge density at the center of the segment cable insulation; />
Representing an empirical value, a standard charge density of the center of the insulation layer of the predetermined cable, obtained from a priori knowledge,/-, a>
The larger the insulation layer, the worse the insulation of the insulation layer of the cable.
In the calculation formula of the degree of abnormality of each section of cable insulation layer, the charge density of the insulation layer center inside the cable reflects the insulation degree of the section of cable at the moment, and when breakage or aging occurs, the charge density in the corresponding insulation layer increases, so that the amplitude of the charge density of the insulation layer center reflects the degree of abnormality of the section of cable to a certain extent.
S6, calculating the degree of abnormality of each section of cable at each moment in the second period according to the charge density of each section of cable at each moment in the second period of the change curve corresponding to each section of cable, a preset charge density decay function of the cable during production test and the charge density corresponding to the first moment.
Normally, when no direct current voltage is applied, no space charge distribution exists between the cable insulation layers, but after the direct current voltage is applied, the internal charge density of the cable insulation layers has a relatively stable attenuation trend, namely the cable insulation layers are increased to the wire cores to a certain extent, and then the attenuation trend is shown until the attenuation trend is zero, although the attenuation trend has smaller fluctuation, the overall characteristics of the data are approximately the same, but if the cable has the problems of aging, breakage and the like, the characteristic of the cable is that the attenuation speed is reduced, or the characteristic of dense space charge distribution on one section is shown, so that the abnormal degree of each section of the cable at each moment in the second period is calculated based on the characteristic.
The calculation formula of the degree of abnormality of each section of cable at each moment in the second period is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
indicate->
The segment cable is +.>
Degree of temporal anomalies; />
Indicate->
The corresponding change curve of the segment cable is +.>
The charge density at time; />
Representing the charge density decay function of the preset cable at the production test as +.>
A value corresponding to the moment; />
Indicating the propagation of sound waves to the +.>
And the charge density corresponds to the time of the outer surface of the insulating layer of the section cable.
Abnormal process of each cable in each time in the second time periodIn the calculation formula of the degree, the first is
For example, the abnormal degree is the difference between the charge density corresponding to the t moment and the charge density corresponding to the attenuation function, and the greater the difference is, the more abnormal the attenuation is, and the greater the abnormal degree is; wherein->
Indicating the charge density at time t +.>
Representing the charge density decay function of the preset cable at the production test as +.>
A value corresponding to the moment; />
Indicating the propagation of sound waves to the +.>
The charge density corresponding to the moment of the outer surface of the insulating layer of the segment cable represents the maximum charge density in the cable. />
The ratio of the difference between the charge density at the time t and the standard value corresponding to the difference to the maximum charge density in the cable is shown, and the greater the ratio is, the greater the degree of abnormality at the time is.
Thus, the degree of abnormality of each section of cable at each time in the second period is obtained.
And S7, calculating the overall abnormality degree of each section of cable according to the abnormality degree of each section of cable insulating layer and the abnormality degree of each section of cable at each moment in the second period.
The step of calculating the overall degree of anomaly of each section of cable comprises the steps of: accumulating the abnormal degree of each section of cable at each moment in the second period to obtain the accumulated value of all the abnormal degrees of each section of cable at all moments in the second period; and adding the accumulated value of all the time abnormal degrees of each section of cable in the second period to the abnormal degree of each section of cable insulating layer to obtain the integral abnormal degree of each section of cable.
The calculation formula of the overall abnormality degree of each section of cable is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
indicate->
The overall abnormality degree of the section cable; />
Indicate->
Degree of abnormality of the segment cable insulation layer; />
Indicate->
The segment cable is +.>
Degree of temporal anomalies; />
Indicate->
A second moment of the segment cable; />
Indicate->
A third moment of the segment cable; />
Namely +.>
The time period between the second time and the third time of the section of cable, namely the time period between the time when the sound wave propagates to the inner surface of each section of cable insulation layer and the time when the sound wave propagates to the outer surface of the cable core insulation layer; />
Representing the interior space of the section of cable, i.e.)>
Is added to the degree of abnormality at each time.
In the calculation formula of the overall abnormality degree of each section of cable, the abnormality degree of the data at each moment is obtained based on the standard value, so that the obtained sum of the abnormality degrees of the data at each moment reflects the abnormality information of the corresponding section of cable to a certain degree; weighting and summing the obtained abnormal degrees corresponding to each moment to obtain a cable section
Corresponding degree of abnormality->
I.e. the degree of abnormality of the length of cable is summed up by the degree of abnormality of its inner insulation layer and the degree of abnormality at each moment in the inner space->
The greater the degree of anomaly, the greater the degree of anomaly that represents the length of cable.
According to the difference degree between the actual measured value and the standard parameter, each section of cable in the cables to be tested is obtained in a second period
The degree of abnormality at the moment, which is obtained based on the standard parameters, is more accurate than the degree of abnormality which is obtained by simply analyzing the fluctuation characteristics thereof, while for each section of cable, the degree of abnormality at each moment in the second period,the adjustment value of the corresponding standard value along with the position information is set based on the attenuation characteristic along with the position information, so that the hidden trouble of actual abnormal information reduction caused by the same standard is avoided.
S8, constructing a Huffman tree according to the overall anomaly degree of all the sections of cables in the cable to be tested from high to low, and carrying out Huffman coding and transmission according to the constructed Huffman tree.
The step of constructing the Huffman tree according to the sequence from high to low by the overall abnormality degree of all the sections of the cables to be tested comprises the following steps: sequencing the overall abnormal degrees of all sections of cables in the cable to be tested according to the sequence from high to low to obtain an overall abnormal degree sequence; taking a first overall anomaly degree value in the overall anomaly degree sequence as a first layer of the Huffman tree, taking a second overall anomaly degree value in the overall anomaly degree sequence as a tree node on the left side of the second layer of the Huffman tree, and taking a third overall anomaly degree value in the overall anomaly degree sequence as a tree node on the right side of the second layer of the Huffman tree, thus completing the construction of the Huffman tree in turn; after the Huffman tree is built, huffman coding is carried out according to the built Huffman tree, and the Huffman coded data is transmitted.
As shown in fig. 4, a schematic diagram of huffman tree is constructed according to the present invention, and each segment of the cable is subjected to the huffman coding rule
According to the degree of abnormality->
Performing descending order sorting so that each cable obtains the descending order of the cables based on the degree of abnormality of the cable>
I.e. +.>
In descending order of +.>
One cable section corresponding to the position, namely +_maximum abnormality degree>
The method comprises the steps of arranging the second bit, the third bit and the fourth bit at the top of a Huffman tree, arranging the second bit, the third bit and the fourth bit in the second layer, arranging the fifth bit in the third layer, namely the right side of the second layer, until all data are arranged in the third layer, and defining each layer, wherein the left corresponding code is 0, and the right corresponding code is 1, so that Huffman coding of the data is completed, and a Huffman coding table is correspondingly generated.
Meanwhile, after the encoding is finished, the data with larger degree of abnormality is located at a position closer to the top end of the Huffman encoding tree, the corresponding encoding sequence is also shorter, the transmission speed is higher due to the shorter encoding sequence in the transmission and storage process through the operation, and meanwhile, the probability of data missing caused by network fluctuation is also smaller; and adjusting the data in the cable and the coding sequence of the cable in the whole cable according to the degree of abnormality, so that the data with higher degree of abnormality is coded more and the data sequence is safer as the transmission speed is higher.
The invention provides a cable charge test data transmission method, which is characterized in that the whole abnormal degree of each section of cable is calculated according to the abnormal degree of each section of cable insulating layer and the abnormal degree of each section of cable at each moment in a second period, and the coding sequence of each section of cable in the whole cable is adjusted according to the whole abnormal degree of each section of cable, so that the shorter the data coding sequence with higher abnormal degree is, the faster the corresponding transmission speed is, and the transmission safety of the data with higher abnormal degree is ensured.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (3)
1. A method of cable charge test data transmission, the method comprising:
acquiring a change curve of charge density of each section of cable in the cable to be tested along with the propagation time of the sound wave, and simultaneously acquiring a first moment when the sound wave propagates to the outer surface of each section of cable insulation layer, a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer and a third moment when the sound wave propagates to the outer surface of each section of cable core insulation layer;
recording a time period between a first time and a second time of each section of cable as a first time period;
recording the time period between the second time and the third time of each section of cable as a second time period;
taking the minimum value of the charge density of the change curve corresponding to each section of cable in the first period as the charge density of the center of the insulating layer of each section of cable;
calculating the degree of abnormality of each section of cable insulating layer according to the charge density of the center of each section of cable insulating layer and the standard charge density of the center of the preset cable insulating layer;
the step of calculating the degree of abnormality of each section of cable insulation layer comprises:
calculating a first difference value between the charge density of the center of each section of cable insulation layer and the standard charge density of the center of the preset cable insulation layer;
calculating a first ratio of a first difference value corresponding to each section of cable to a standard charge density of the center of a preset cable insulating layer;
taking the absolute value of the first ratio corresponding to each section of cable as the abnormal degree of the insulating layer of each section of cable;
calculating the degree of abnormality of each section of cable at each moment in the second period according to the charge density of each section of cable at each moment in the second period of the change curve corresponding to each section of cable, a charge density decay function of a preset cable during production test and the charge density corresponding to the first moment;
the calculation formula of the degree of abnormality of each section of cable at each moment in the second period is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
indicate->
The segment cable is +.>
Degree of temporal anomalies; />
Indicate->
The corresponding change curve of the segment cable is +.>
The charge density at time; />
Representing the charge density decay function of the preset cable at the production test as +.>
A value corresponding to the moment; />
Indicating the propagation of sound waves to the +.>
The charge density corresponding to the first moment of the section cable;
calculating the overall abnormality degree of each section of cable according to the abnormality degree of each section of cable insulating layer and the abnormality degree of each section of cable at each moment in the second period;
the step of calculating the overall degree of anomaly of each section of cable comprises the steps of:
accumulating the abnormal degree of each section of cable at each moment in the second period to obtain the accumulated value of all the abnormal degrees of each section of cable at all moments in the second period;
adding the accumulated value of all the moment abnormal degrees of each section of cable in the second period of time to the abnormal degree of each section of cable insulating layer to obtain the integral abnormal degree of each section of cable;
constructing a Huffman tree according to the sequence from high to low of the overall abnormality degree of all the sections of cables in the cable to be tested;
the step of constructing the Huffman tree according to the sequence from high to low by the overall abnormality degree of all the sections of the cables to be tested comprises the following steps:
sequencing the overall abnormal degrees of all sections of cables in the cable to be tested according to the sequence from high to low to obtain an overall abnormal degree sequence;
taking a first overall anomaly value in the overall anomaly degree sequence as a first layer of a Huffman tree, taking a second overall anomaly value in the overall anomaly degree sequence as a left tree node of a second layer of the Huffman tree, taking a third overall anomaly value in the overall anomaly degree sequence as a right tree node of the second layer of the Huffman tree, and placing a fourth overall anomaly value and a fifth overall anomaly value on the right side of a third layer which is the next layer of the third overall anomaly value according to the sequence until all data are placed in the Huffman tree, and defining that the corresponding code on the left side is 0 and the right side is 1 in each layer, thus finishing Huffman coding of the data and correspondingly generating a Huffman coding table;
and carrying out Huffman coding according to the constructed Huffman tree and transmitting.
2. The method of claim 1, wherein the step of obtaining a first time of propagation of the acoustic wave to the outer surface of each section of cable core insulation layer, a second time of propagation of the acoustic wave to the inner surface of each section of cable core insulation layer, and a third time of propagation of the acoustic wave to the outer surface of each section of cable core insulation layer comprises:
the moment corresponding to the first wave crest in the change curve is used as the first moment when the sound wave propagates to the outer surface of each section of cable insulation layer;
calculating a second moment when the sound wave propagates to the inner surface of each section of cable insulation layer according to the preset standard thickness of the cable insulation layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulation layer;
and calculating a third moment when the sound wave propagates to the outer surface of each section of cable core insulating layer according to the preset standard distance between the outer surface of the cable core insulating layer and the outer surface of the cable insulating layer, the preset sound wave propagation speed and the moment when the sound wave propagates to the outer surface of each section of cable insulating layer.
3. The method of claim 1, wherein the step of obtaining a plot of charge density versus time of propagation of acoustic waves for each segment of the cable to be tested comprises:
and transmitting sound waves by using the coaxial cable space charge measuring device, and testing the change curve of the charge density of each section of cable along with the propagation time of the sound waves.
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